Newborn infants, both preterm and term, may experience respiratory distress as a result of various conditions including respiratory distress syndrome of the newborn (a.k.a. hyaline membrane disease), wet lung syndrome of the newborn, intrauterine pneumonia, postnatal pneumonia, meconium aspiration syndrome, persistent pulmonary hypertension of the newborn (a.k.a. persistent fetal circulation), pulmonary hypoplasia, and certain neurological conditions. Some newborn infants with respiratory distress are judged to require treatment with different types of respiratory support.
In the context of systems for delivering respiratory support, nasal cannulas are devices that deliver gases directly to the nares of a patient. There are two primary types of nasal cannulas: standard nasal cannulas and limited-leak cannulas. Standard nasal cannulas are used to deliver gases into the nares at a fixed flow rate. In contrast, limited-leak cannulas are used by setting a pressure level or levels rather than flow rate(s). In order to function properly, the prongs of a limited-leak cannula, though larger than those of a standard cannula, cannot form a seal with the nares, but rather a leak is required at the nasal level allowing continuous unidirectional flow. An example of a limited-leak cannula is the RAM Cannula commercially available from Neotech Products, Inc., Valencia, Calif.